Apparatus for controlling series of operations



June 1954 A. s. BEECH ETAL 3,136,335

APPARATUS FOR CONTROLLING SERIES OF OPERATIONS Filed Nov. 17, 1961 3Sheets-Sheet 1 5 Sheets-Sheet 2 A. S. BEECH ETAL June 9, 1964 APPARATUSFOR CONTROLLING SERIES OF OPERATIONS Filed Nov. 17, 1961 June 9, 1964 A,5, BEECH ETAL 3,136,335

APPARATUS FOR CONTROLLING SERIES OF OPERATIONS Filed NOV. 17, 1961 5Sheets-Sheet 3 United States Patent 3,136,335 APPARATUS FOR CONTROLLINGSERIES OF OPERATIONS Austin Sidney Beech and Thomas Spencer, both ofLeighton Buzzard, England, assignors to Austin S. Beech & CompanyLimited, Leighton Buzzard, England, a British company 9 Claims. (Cl.137-624.13)

This invention comprises improvements in or relating to apparatus forcontrolling series of operations.

In many machines which are automatically operated it is necessary for acycle of operations to be automatically repeated but the times of thevarious operations are not rigidly fixed and a new operation can only becommenced when a signal is given by the apparatus that a formeroperation has been completed. Such conditions occur for example inautomatic foundry moulding machines, in die-casting or plastic injectionmoulding machines, in automatic machine tools and in many other kinds ofapparatus which may be operated pneumatically, hydraulically orelectrically.

It is an object of the present invention to provide a unit forcontrolling such operation, which is adaptable to a variety ofconditions and which serves to gather together in itself a large part ofthe essential features of control and thus to simplify the layout of themachine.

According to the present invention a unit for controlling the initiationof a series of operations in accordance with signals delivered to it,comprises in combination a control rotor, means for rotating itstepwise, a signalreceiver movable stepwise by the control rotor, aseries of signal-delivery elements disposed so that the signalreceiverregisters with one delivery element at each step and is then capable ofreceiving a signal therefrom, means whereby the signal receiver, onreceipt of a signal, energises the means for rotating the control rotorto move it one step, whereby the signal-receiver is moved into registerwith the next signal-delivery element, and an operation controllermovable stepwise by the control rotor and capable in its variouspositions of initiating different operations.

The nature of the signals, the means for rotating the control rotor andthe nature of the control exercised by the operation controller mayvary.

In the form of unit hereinafter described the means for rotating thecontrol rotor stepwise consists of a pneumatically-operated ratchetmechanism and the signals received by the signal-receiver are pneumaticpulses, but in either case electrical or hydraulic means might beadopted. The operation controller may actuate either a pneumatic circuitor an electrical or hydraulic or other control circuit.

In the preferred form of apparatus the signal-receiver actuates apneumatic or electrical relay by which the power applied to the step bystep mechanism is amplified. The operation controller may also actuate arelay if desired.

In some instances it is desirable to hold a machine part which has beenmoved in one operation while other operations proceed, and not to returnit to its initial position until a later point in the cycle. Accordingto the present invention this can be allowed for by the addition ofappropriate cam or like mechanism to the operation controller, in'suchmanner as to actuate holding valves or the like over various portions ofthe cycle, and preferablythe control unit is so constructed that thechanging of cams for this purpose is a quick and simple operation.

The following is a description, by way of example, of one constructionin accordance with the invention:

Referring to the accompanying drawings,

FIGURE 1 is a vertical section of the apparatus, upon the line 1--1 ofFIGURE 3, looking in the direction of the arrows;

Patented June 9, 1964 FIGURE 2 is a plan, with cover removed;

FIGURE 3 is a side elevation partly in section looking from the left asviewed in FIGURE 1;

FIGURE 4 is a section on the line 44 of FIGURE 4, looking in thedirection of the arrows, and

FIGURE 5 is a diagram of connections.

The unit comprises a casing 11 having a removable cover 12 andcontaining a control rotor which takes the form of two ratchet wheels13, 14 mountedon a shaft 15 which passes through one wall of the casingand is supported in ball hearings in a thick block 16 of metal securedto the outside of the wall and hereinafter referred to as thesignal-block. The part of the rotor shaft 15 inside the casing 11 whichcarries the ratchet wheels is overhung and extends only a part of theway across the casing. Each ratchet wheel has six teeth and they arekeyed to the shaft so that the teeth of one wheel are midway between theteeth of the other wheel, thus forming in effect a 12-toothed ratchet.

Extending across the casing at right angles to the rotor shaft 15 and inthe space beyond the end of the shaft, is a fixed piston rod 17, bestseen in FIGURE 2, which carries a piston 18 at its centre. The pistonrod 17 is gripped endwise firmly between socket members 19, 20 which arescrewed into lugs 21, 22 in the wall of the casing 11'opposite each endof the rod and prevent the rod from moving. The screwed exterior of thesocket member 19, 20 extends into thecasing and each member carries ascrewed sleeve 23, the end of which projects from the socket memberaround the piston rod and carries a rubber buffer 25. On the piston rodthere slides a double-acting cylinder 24, the ends of which are closedby appropriate fittings 26, 27 which carry fluid-tight glands 28. Thecylinder 24 has a limited stroke between the buffers 25.

Owing to the fact that the cylinder reciprocates, fluid pressureconnections for operating it are not taken to it direct, but are takenthrough the centre of the piston rod 17, one from each end, by fluidpassages 29, 30 in the rod and passages 31, 32 leading through thescrewed sleeves 19 and 20 which hold the rod in place.

In the casing 11 below the cylinder and parallelwith its directionofmovement, there is secured a guide bar 33 (FIGURE 1) and lugs,34 onthecylinder ends extend downwardly into engagement with the guide bar 34 sothat the cylinder is prevented from rotating about the axis of thepiston rod 17. Each end of the cylinder furthermore carries one of twolugs 35, 36 on which are pivoted two pawls 37, 38 respectively, one pawl37 being above the ratchet wheels and the other 38 below. The plane ofmovement of the pawls is such that the lower one engages with theoutermost ratchet wheel 14 of the control rotor and the upper oneengages with the inner wheel 13. The two pawls are drawn towards oneanother and therefore towards the ratchet teeth by a spiral tensionspring 39 which extends between them. The lugs 35, 36 which carry thepawls are formed in one piece with the body of the cylinder 24 andassociated with each lug is a flat face 40 or 41 on the side of thecylinder which faces towards the ratchet wheels and is slotted in adirection parallel to the movement of the cylinder to receive twoadjustable stops 42, 43. The stops are secured in the slots in the flatface by set-screws 44 passing through the slots in the faces 40, 41 andeach stop occupies such a position that when the cylinder has completeda stroke in one direction, carrying with it the pawls 35, 36 whichengage the ratchet wheels, and one of the pawls causes the rotor toadvance one-twelfth of a revolution, the stop will engage the back ofanother tooth on the ratchet wheel and prevent overrun. For example, inFIGURE 1 the stop 38 is shown as having advanced the rotor by engage- 1ment with one of the teeth of ratchet wheel 14 and the will engage theback of a ratchet tooth and again prevent overrun. The stops can beexactly adjusted along the slots in which they are mounted by looseningtheir setscreWs 44 and screwing up or unscrewing an adjusting setscrew45 or 46 which passes through a flange (47 or 48) on the end of one ofthe flat faces 40, 41 above' referred to, in a direction parallel to themovement of the cylinder. Thus great exactitude of movement of the rotorat each step is afforded without any possibility of overrunning ormissing a tooth.

In the wall of the casing 11 opposite to the wall which carries thesignal-block 16 and at a lever below the axis of the rotor shaft, thereis a lug 50 through which passes a rock shaft 51 (FIGURE 3). rock shaftcarries a crank 52 and a crank pin 53 and the crank pin engages avertical slot 54 in the wall of the cylinder 24 which lies opposite tothe ratchet mechanism. Outside the casing the rock shaft carries asquare 55 and if a spanner or key is applied to the square the cylindercan be reciprocated by hand, without the use of fluid pressure, to movethe control rotor stepwise, either for the purpose of testing, orsetting the ratchet stops, or of controlling a part of a machine cycleby hand.

Outside the signal-block 16 the rotor shaft 15 has a head on which ismounted a disc 61 hereinafter referred to as the signal-receiver. Thesignal-receiver has a ground and polished or lapped face 65 which bearsagainst a series of signal-delivery elements 62 carried by thesignal-block 16. The signal-delivery elements 62 consist of twelvenozzles Which have stems 67 and are secured by nuts 68 in a rubberdiaphragm 64 carried by the signal-block and the nozzles are disposed intwo circles of different diameter as shown in FIGURE 4 so that a nozzlein the circle of smaller diameter alternates with anozzle in the circleof larger diameter. The rubber diaphragm is clamped by a suitableclamping plate 63 firmly to the signal-block 16. The clamping plate 63has apertures 66 which surround the nozzles 62 with a clearance. It issecured to the block 16 by screws 67. Each of the nozzles lies in frontof a signal air chamber '70 bored in the signal-block and the airchamber contains a spiral spring 71 which together with the air pressureurges the nozzle into contact'with the polished face 65 of the rotatablesignal-receiver. Radial tapped holes 72 around the periphery of thesignal-block communicate with the air chambers by radial passages 68, s9and a signal pipe can be led to each tapped hole.

The signal-receiver 61 carries twoports 73, 74 which are diametricallyopposite to one another, one port 74 being at a radius corresponding tothe outer circle of signal-nozzles 62 and the other port '73 at a radiuscorresponding to the inner circle. As a result, in any given position ofthe signal-receiver, one port (73 or 74) will be in communication with anozzle of its circle and the other port will be in communication withthe space between two nozzles of the other circle. If the signalreceiveris rotated through one-twelfth of a revolution by the ratchet-controlrotor, the port which was in communication with a nozzle will finditself in communication with the space between two nozzles, and theother port which was in communication with the space will find itself incommunication with a nozzle. If pressure is delivered through thenozzles the ports will therefore receive pressure alternately and willbe alternately connected to the space between nozzles, which is incommunication with the space 75 around the signal-receiver 61 and withexhaust port 76.

The two ports in the signal-receiver communicate by drilled passages 77,78 with two parallel passages .79, 80

Within the casing the.

drilled in the rotor shaft 15, and these passages extend to ports 81, 82in the side of the'shaft where it passes through the signal-block 16between the two ball bearings. The ports 81, 82 register with twoannular recesses 83, 84 in the signal-block which are sealed off bysealing rings 85 between then and on each side. The annular recesses areconnected by radial passages 86, 87 in the underside of the signal-blockto two signal-pipes 88,89.

The signal-pipes lead to the opposite ends of a pneumatically-operatedvalve 90 secured to the underside of the control rotor casing. Thisvalve contains a shuttle valve-member of the usual type and is suppliedwith compressed'air at the opening 91 (FIGURE 1), which the shuttlevalve distributes to one or other of two pipe connections 92, 93/ Theconnection 92 is connected by a pipe 94, indicated by a chain-line, tothe screwed member 19 and thence by passage 29 to the left-hand end ofcylinder 24. The connection 93 goes by pipe 95 to the other end of thecylinder. The valve 90 thus serves to deliver compressed air alternatelyto the two ends of the air cylinder of the ratchet mechanism. If onesignal-pipe 88 or 89 is supplied with pressure and the other connectedto exhaust, the ratchet cylinder is moved in one direction, and if theother signal-pipe is supplied with pressure and the first connected toexhaust the ratchet cylinder is moved back.

The rotary signal-receiver 61 contains in its opposite face to thatwhichis secured to the rotor shaft a recess which receives the head 96of the shaft 97 of an operation-controller and which will therefore bereferred to as the operation-control shaft. The operation-controller maytake various forms but in the particular form about to be described thesignal-receiver 61 itself contains passages which form partof theoperation-controller, the cooperating part of which'is a fixed valveblock 98. In the construction described the operation-controller at eachstep of the ratchet mechanism can supply air under pressure to one of aseries of operation pipes 99 which are connected to the valve block 98.Each pipe 99 is intended to lead to a jack or motor or the like, such asone of those shown at 100, 101, 102, FIGURE 5, which is set in operationwhen the controller delivers air to the pipe and when the jack or other.device has completed a movement it will actuate a limit valve 103, 104or 105 for sending air by means of a signal-pipe 106, 107 or 108 to oneof the signal air-chambers 70 in the signal-block 16. If the pipeconnections are properly made the effect will be that signal air,entering the air chamber 70 will be led by the signal-controller to theappropriate end of the pneumatically-operated valve 90 which will beactuated to cause the ratchet mechanism to make one single stroke. Thiswill reverse the connections to the signalpipes 88, 89 between thesignal-block 16 and the valve, but it will not reverse the valve untilthe next air chamber 70 in the signal-block receives air upon thetermination of the next machine operation. Accordingly the ratchetmechanism makes no further movement until the next machine operation iscompleted.

The operation-controller valve-block 98, when the ratchet mechanism hasmoved a step, directs air to the next jack or motor'or the like on themachine and when this has completed a machine movement it sends back asignal to the signal-block which enables another step to be made. Thusthe operations proceed under the control of the unit without any furthercomplication beyond the necessary pipework between the unit and thevarious jacks or motors of the machine.

The construction of the operation-controller in the particular examplenow being described is as follows:

The fixed cylindrical valve block 98 is secured to the signal-block 16by means of an intermediate sleeve 110 which surrounds the rotarysignal-receiver 61 and by setscrews 111 which secure the whole together.The valve block 98 contains a bearing bush 112 for the operation controlshaft 97 which shaft projects outwardly beyond the block. The inner face114 of the valve block is ground and lapped and contains a circle oftwelve ports 115, most of which, or as many of which are necessary forthe operations of the machine, are connected to the air pipes 99 leadingto the jacks or motors on the machine. The face of the signal-receiverdisc 61 which lies towards the ports acts as a distributor and carries anozzle-holding ring 116 in which there is mounted slidably a nozzle 117capable of registering with the ports and pressed towards them by aspring 118. The nozzle is sealed by a sealing ring 119 to the ring 116and a passage 120 within the disc 61 communicates with a passage 121 inthe centre of the operation-control shaft 97. This passage communicateswith an annular recess 122 around the shaft in the centre of theoperation-control block 98 and the recess is connected by a radialtapped hole 123 with an air supply pipe. Thus at each stop the nozzle117 will supply air under pressure to a different port 115 and thence byone of the pipes 99 to a jack such as 100 of the machine. The spacearound the nozzle 117 is in communication with the annular space 75surrounding the signal-receiver which is open to exhaust at 76. Thus allthe jacks except the one which is being supplied with pressure will beconnected to exhaust.

If this were all, every jack could only be operated during one step ofthe machine, but in some cases this is not sufficient because a jack mayrequire to be held on, while other operations are proceeding. To enablethis to be done cams 124, 125 can be mounted on the end of theoperation-control shaft, which control valves (not shown in FIGURE 3) inthe circuit leading to the jacks or motors 100, 101 or 102. Any one jackor motor can be held on after it has completed a stroke for as long asdesired by operating a hold-on valve 126 (FIGURE 5 through one of thecams 124 or 125 the valve being arranged in the pipe leading to thatjack or motor. Thus, any desired combination of operations can beeffected.

It will be obvious that instead of ports for compressed air, thesignal-receiver might be arranged with electric contacts to be energisedfor electric signal lines and similarly the operation-controller mightoperate through electric contacts instead of by a movable nozzle. Theratchet mechanism might also be electromatically-operated instead of bycompressed air. Alternatively, some or all of these operations might beeffected hydraulically or by any other form of power applied.

We claim:

1. A control unit for the purpose described comprising in combination arotor shaft, pneumatically-operated ratchet means for rotating the rotorshaft stepwise, a signal-rotor forming part of a signal-receiver mountedupon the rotor shaft having a rotatable valve-face containing a port, astationary signal block, forming another part of the signal-receiver,adjacent to the signalrotor and having a plurality of ports with whichthe ports in the signal-rotor registers seriatim, passages in the signalblock to connect the ports thereof with signal pipes, means to connectthe port in the signal-rotor with the pneumatically-operated ratchetmechanism to actuate the same upon receipt of a pneumatic pulse throughone of the ports in the signal-block of the signal-receiver, anoperation-controller having a movable element which is mounted on therotor shaft and carries an operation-control port, the operation-controlport at each step of the rotor shaft registering with one of a series ofports in a fixed distribution-block and means to connect the ports inthe distribution-block to pipes for operating parts of a machine whichis to be controlled by the unit.

2. A control system for a machine having self-acting devices foreffecting its functions, comprising a control unit as claimed in claim1, limit-valve means for actuation by moving parts of the machine at theconclusion of each self-acting operation of the machine, means forconnecting said limit-valve means to the signal-receiver of the controlunit to accord signals thereto and means connecting theoperation-controller at each step of the unit to the appropriateself-acting device on the machine to effect the next function.

3. A control unit for the purpose described comprising in combination arotor shaft, fluid pressure operated ratchet means for rotating therotor shaft stepwise, a signal-rotor forming part of a signal-receivermounted upon the rotor shaft having a rotatable valve-face containing aport, a stationary signal block forming another part of thesignal-receiver, adjacent to the signal-rotor and having a plurality ofports with which the port in the signal-rotor registers seriatim,passages in the signal block to connect the ports thereof with signalpipes, means to connect the port in the signal-rotor with thefluid-pressure operated ratchet mechanism to actuate the same uponreceipt of a pressure pulse through one of the ports in the signal-blockof the signal-receiver, an operation-controller having a movable elementwhich is mounted on the rotor shaft and carries an operation-controlport, the operation-control port at each step of the rotor shaftregistering with one of a series of ports in a fixed distribution-blockconnected to pipes for operating parts of a machine which is to becontrolled by the unit.

4. A control unit as claimed in claim 3, wherein the fluid pressureoperated ratchet means for rotating the rotor shaft are operable bypneumatic pressure.

5. A control unit as claimed in claim 3, wherein between the signalreceiver and the fluid-pressure operated ratchet means there isinterposed a fluid-pressure relayvalve.

6. A control unit as claimed in claim 4, wherein the movable element ofthe operation-controller is formed as part of the same block as thesignal-rotor.

7. A control unit as claimed in claim 1 wherein between thesignal-receiver and the pneumatically-operated ratchet mechanism thereis interposed a pneumatic relayvalve.

8. A control unit for a fluid-pressure operated system of motorscomprising in combination an operation controller comprising a rotatableelement having an operation-control port with a supply conduit for fluidpressure thereto and a distribution block having a series of ports overwhich the control-port moves seriatim, with distribution conduitsextending therefrom, a signal receiver comprising a rotatable portedsignal-rotor operatively connected to the movable element of theoperation-controller to move therewith, a stationary signal block injuxtaposition to the rotor having a series of signal ports over whichthe ported signal rotor moves and conduits extending thereto,fluid-pressure operated ratchet means operatively connected to therotatable element of the operation controller and of the signal rotor tomove them together stepwise, and conduit means connecting the portedsignalrotor to the operating-means of the ratchet-means.

9. A control system for a machine having self-acting devices foreffecting its functions, comprising a control unit as claimed in claim8, limit-valve means capable of operation by moving parts of the machineat the conclusion of each self-acting operation, pipes communicatingsaid limit-valve means to the passages in the signal block, and pipesconnecting the distribution conduits of the operation controller to theappropriate self-acting devices, on the machine, to effect thesuccessive functions.

References Cited in the file of this patent UNITED STATES PATENTS 25,132Mitchell Aug. 16, 1859 1,078,151 Lamb Nov. 11, 1913 1,745,707 PerrettFeb. 4, 1930 1,851,502 Ferris et al Mar. 29, 1932 FOREIGN PATENTS814,622 Great Britain June 10, 1959

1. A CONTROL UNIT FOR THE PURPOSE DESCRIBED COMPRISING IN COMBINATION AROTOR SHAFT, PNEUMATICALLY-OPERATED RATCHET MEANS FOR ROTATING THE ROTORSHAFT STEPWISE, A SIGNAL-ROTOR FORMING PART OF A SIGNAL-RECEIVER MOUNTEDUPON THE ROTOR SHAFT HAVING A ROTATABLE VALVE-FACE CONTAINING A PORT, ASTATIONARY SIGNAL BLOCK, FORMING ANOTHER PART OF THE SIGNAL-RECEIVER,ADJACENT TO THE SIGNALROTOR AND HAVING A PLURALITY OF PORTS WITH WHICHTHE PORTS IN THE SIGNAL-ROTOR REGISTERS SERIATIM, PASSAGES IN THE SIGNALBLOCK TO CONNECT THE PORTS THEREOF WITH SIGNAL PIPES, MEANS TO CONNECTTHE PORT IN THE SIGNAL-ROTOR WITH THE PNEUMATICALLY-OPERATED RATCHETMECHANISM TO ACTUATE THE SAME UPON RECEIPT OF A PNEUMATIC PULSE THROUGHONE OF THE PORTS IN THE SIGNAL-BLOCK OF THE SIGNAL-RECEIVER, ANOPERATION-CONTROLLER HAVING A MOVABLE ELEMENT WHICH IS MOUNTED ON THEROTOR SHAFT AND CARRIES AN OPERATION-CONTROL PORT, THE OPERATION-CONTROLPORT AT EACH STEP OF THE ROTOR SHAFT REGISTERING WITH ONE OF A SERIES OFPORTS IN A FIXED DISTRIBUTION-BLOCK AND MEANS TO CONNECT THE PORTS INTHE DISTRIBUTION-BLOCK TO PIPES FOR OPERATING PARTS OF A MACHINE WHICHIS TO BE CONTROLLED BY THE UNIT.